Fusion researchers see frozen pellet tech as way to control ITER's plasma as well as fuel it

November 3, 2011
by Agatha Bardoel

A large (+16 mm) pellet is undergoing testing for ITER disruption mitigation. The pellet, on the left, is exiting the guide tube just before hitting a simple target plate. It will shatter once it hits the plate. (Photo: Combs, ORNL)

(PhysOrg.com) -- Heated to extreme temperatures of up to 150 million degrees Celsius, the plasma in ITER's giant experimental fusion reactor will be fed a fuel of frozen pellets of deuterium-tritium, fired into the tokamak vacuum vessel by pellet injectors. Testing of the most recent pellet injection design technology developed by Oak Ridge National Laboratory and US ITER is under way this fall at the DIII-D research tokamak in San Diego, operated by General Atomics for the Department of Energy through the Office of Fusion Energy Sciences.

The design, testing, and manufacture of this pellet injection system is one of the key contributions of the United States to ITER, an international collaboration that is committed to building the largest ever tokamak in southern France. Tokamaks are doughnut-shaped machines that use magnetic fields to contain hot plasma. The goal of ITER is to demonstrate the feasibility of fusion energy for commercial-scale electricity; "first plasma" for the experimental facility is planned for 2020.

Physicist David Rasmussen serves as the lead for US ITER's fueling team and as a group leader in the Fusion Energy Division at Oak Ridge National Laboratory. He points out that understanding of the plasma fuel in a fusion reactor has evolved over several decades, and pellet injection is now seen as a compelling method to control potential plasma instability inside the reactor. The US ITER fueling team, which includes physicists, engineers, technicians, and other experts, collaborates closely with the international fusion science community to integrate key research findings in plasma fueling and control.

The pellets are made of deuterium and tritium, isotopes of hydrogen that are frozen at 11 degrees above absolute zero Kelvin. When they are fired into the tokamak by a pulse of high-pressure gas, they vaporize and the particles are ionized, becoming part of the plasma. Inside the tokamak, the deuterium particles are heated up to as much as 200 million degrees Kelvin, or more than 10 times the temperature inside our sun.

"When we send a frozen pellet into a high-temperature plasma, we sometimes call it a 'snowball in hell'," Rasmussen said in an interview. "But temperature is really just the measure of the energy of the particles in the plasma. When the deuterium and tritium particles vaporize, ionize, and are heated, they move very fast, colliding with enough energy to fuse." The energy released from the fusion reaction, as energetic neutrons and helium, has potential as an abundant, carbon-free energy source.

But pellets are not just about fuel. Research has found that the pellets can also control spontaneous instabilities which occur at the edge of the plasma, called edge localized modes (ELMs). If the full energy of these ELMs is absorbed by the machine, erosion of plasma-facing surfaces can occur. Small pellets can be used to reduce the size of the ELMs into more frequent but less harmful events, a task researchers like to call "burping the baby," Rasmussen said. In addition, larger pellets about the size of a wine cork can be injected to break down the plasma column altogether. This contingency comes into play should operators need to stop the plasma racing around the reactor. The large pellets can collapse the plasma "to give it a safe landing," said Rasmussen.

The fueling and instability issues are caused by the nature of plasma itself. Plasma, the fourth state of matter, is an ionized gas that includes positively and negatively charged particles. "We apply very high magnetic fields, and the plasma reacts to those," Rasmussen explained. "The plasma has its own internal currents, and a whole menagerie of instabilities depends on those internal currents. The ELMs are the ones that occur near the outside edge. These are filaments, basically, that spiral around. Such bursts can be intense and can damage the plasma-facing surfaces of the vessel."

Researchers are experimenting with injecting small pellets, a couple of millimeters in diameter, at the plasma edge. This approach imposes additional magnetic fields that break up the ELM spirals into smaller events. "We put a little chaos near the edge," noted Rasmussen. "That tends to make these things unstable, so the edge releases these spirals in a more predictable way."

The researchers have gone through a couple of iterations of the injector that provides these small pellets. They have recently installed a new design on the DIII-D tokamak that is now being tested. The test reactor DIII-D now uses only deuterium pellets, but ITER will use both deuterium and tritium. The researchers are also experimenting with pellets of neon and argon to control plasma events. Research is also proceeding on the wine cork-sized pellet for collapsing a plasma.

"There are certain conditions where the current gets interrupted and gets out of control," Rasmussen said. "Instead of traveling in a controlled or confined way around the tokamak, it shifts upward or downward in the chamber, and comes into contact with the walls where it can potentially cause damage."

Electromagnetic effects that result from this current shift impact the entire tokamak. One option for controlling such disruptions is to inject a massive amount of gas, which collapses the plasma column and cools it. Large pellets are an option being developed at ORNL, since they can cool the plasma even faster.

The gas to control the plasma is frozen in the injector, then accelerated and bounced off a number of metal plates to break it up into particles before entering the plasma. The metal plates shatter the pellets so that shards are sprayed in at several points. "What you see looking across the tokamak is a spray of pellet particles, and then an intense emission of light. That means we are converting the plasma back to gas," said Rasmussen.

One of the things researchers are now trying to decide is how many large pellets they must inject to collapse the plasma. "We think the number is perhaps 4 to 10 at the same time. We are going to do experiments on DIII-D that will help us identify just how much symmetry is required to make this work well." The DIII-D in San Diego is the largest tokamak in the United States and a "good test bed for the system," Rasmussen said. "We have identified four places on the ITER tokamak where we could do gas injection of very large amounts of gas and also of these pellets."

Rasmussen is very conscious that a major challenge remains: How to extend the physics from the conditions at DIII-D to conditions orders of magnitude greater that are expected in the ITER tokamak, which will be 10 stories high. "It is a fairly big leap from DIII-D to ITER. We work with JET, a larger tokamak device in the United Kingdom, as well on pellet injector experiments, so that is closer to conditions on ITER, but it is not the full ITER conditions."

"In addition to the experiments, we and our international colleagues do a lot of modeling," Rasmussen said. "We have to really understand what effects are going on in DIII-D to create accurate models. Then we can run that model for ITER conditions."

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Scam. The resulting copper analyzed had the same isotopic ratio as naturally occurring copper. The only thing your viral marketing is achieving is making you look like an idiot.

I have not invested in neither. But I think we should redirect the hot fusion money to investigate 'cold fusion' or LENR or what ever would be proper name for it. There is way too much of experimental data about it to dismiss it as a hoax. Consider 100K supraconductance. We don't have a good theory about it either, but it's nonethless considered valid area to study. Since at least 1989 LENR has been studied by hundreds of people and now it's beginning to emerge as consistent energy source.

Will hot fusion ever be used for energy production? I think it will be obsoleted by Rossi's E-CAT which is working today and should replace fossil fuels any time soon.

Just to be clear, are you comparing actual scientific research which includes things like test results, observations, public discourse, peer review, etc. with the E-Cat, which has none of these? Clearly, we're just supposed to take Rossi's word for it that it works. Well, that's fine, and I wish him luck. But, the inventor's tinkering shouldn't be compared to real research.

Also, to say that the E-Cat could replace fossil fuels "soon" is to lose any credibility with which you began your statement. Even if the machine worked perfectly, it's in no position to replace anything anytime soon. You clearly have no idea how big industry, energy policy, or economics work.

Scam. The resulting copper analyzed had the same isotopic ratio as naturally occurring copper. The only thing your viral marketing is achieving is making you look like an idiot.

I have not invested in neither. But I think we should redirect the hot fusion money to investigate 'cold fusion' or LENR or what ever would be proper name for it. There is way too much of experimental data about it to dismiss it as a hoax. Consider 100K supraconductance. We don't have a good theory about it either, but it's nonethless considered valid area to study. Since at least 1989 LENR has been studied by hundreds of people and now it's beginning to emerge as consistent energy source.

No, it is NOT beginning to emerge as a "consistent" energy source. This is wishful thinking, not logic, not fact.

You just got linked dozen of publications. Whereas you've no link to support your stance - why I should believe just you, an anonymous troll without any credit? Cold fusion theory is logical and it's described there too. You're just ignoring all evidence.

For a pellet that weighs a few grams at 11 degrees...I would imagine that it is easily affordable.

And at those prices, obviously it can't be more than a few hundred watt hours per pellet. Industrial efficiencies can be much higher than your freezer. it probably takes more energy and care just to handle the frozen pellets.

Now let's compare that to the amount of energy it took to build a 20 billion dollar power plant with giant ass lasers that use exowatts of power...

No, it is NOT beginning to emerge as a "consistent" energy source. This is wishful thinking, not logic, not fact.

So how would you describe the tests done with Rossi's devices this year? Well despite you and me, time will show how LENR will play out. Still I am sure that in 20 years hot fusion is still under study, while LENR has the potential to be a major part of global energy picture.

Now I'm not censored one half or year - although I didn't change my stuffs at least a bit. BTW if previous PO moderators wouldn't censor me, I'd still use my original account for sure. It's all about people at the other side.

You just got linked dozen of publications. Whereas you've no link to support your stance - why I should believe just you, an anonymous troll without any credit? Cold fusion theory is logical and it's described there too. You're just ignoring all evidence.

Callipo, you and I both know that you support Rossi. That's fine. But stating that the E-Cat is not a "consistent" energy device hardly makes me a troll. I don't need to prove anything or link to any sources, of which there are 10s of thousands, to authenticate this because we are talking about the real world. I've said before, if the E-cat does SOMEDAY become a "consistent" energy source, I'll gladly eat my words. But, as of yet, at best you can argue that it's a "new, potentially interesting" energy source. "Consistent" must be reserved for more mature technologies.

No, it is NOT beginning to emerge as a "consistent" energy source. This is wishful thinking, not logic, not fact.

So how would you describe the tests done with Rossi's devices this year? Well despite you and me, time will show how LENR will play out. Still I am sure that in 20 years hot fusion is still under study, while LENR has the potential to be a major part of global energy picture.

At this point, I would describe them as "super duper top secret" hogwash. But that's just me.

I could just as easily describe to you my yet-to-be-seen-or-authenticated power plant based on a gold ring I found at Mt. Doom. Sounds cool. Doesn't make it true.

Until Rossi comes forward OR one of his clients is up and running and publicly showing successful results, this is all just "faith".

Consistent, as in "with a long-term record". Coal/nuclear/oil would be consistent. Wind and solar, too. Many years of working models all over the world for each of these. So, they've been able to be tested, tested some more, and then tested again. And, each is still being studied and perfected today.

"not an expert in giant asses". hehe. Somewhere I suppose someone has this job.

You started to talk about (absence of) consistent theory of cold fusion. A consistent theory of cold fusion indeed does exist (actually, there are many of them already). But to talk about E-cat catalyst like about inconsistent stuff appears semantically inconsistent for me.

Callippo is right that there is consistent and proven cold fusion out there. That actually is not up for question.

However - There has never been any cold fusion method that has come even remotely close to breaking even on energy input. It is highly impractical as it stands, do to enormous entropic losses and poor fusion efficiency. From a practical standpoint, hot fusion is more practical because the energy in the plasma can be contained to some degree with magnetic fields and forced to continue to do positive work.

It's similar in principle to how a giant power plant is more efficient than your car engine.

Whether or not a solution to cold fusion or not, The Rossi E-cat is almost certainly a scam. That will be revealed in the next few years.

If by some miracle, it is not a scam, or he has actually found another mechanism even, it would be awesome, but lets not stop pushing other avenues because one quack says he's got it.

You started to talk about (absence of) consistent theory of cold fusion. A consistent theory of cold fusion indeed does exist (actually, there are many of them already). But to talk about E-cat catalyst like about inconsistent stuff appears semantically inconsistent for me.

OK, just to clarify then. I had to go back and read it all again. The topic was E-cat, and switched to LENR in general in the post where PPihkala was refuting E-Cat being a "scam". Anyway, kind of splitting hairs in my mind. Yes, LENR is considered by a pretty small handful of researchers to be a potentially valid energy source. However, to the best of my knowledge, only Rossi claims that he's got a magic box that can do it. So, I would argue LENR can certainly not be called a "consistent energy source" which is what PPihkala had said originally. Now, wouldn't it be interesting if NASA ends up being his "mystery client"?

"Rossi's first customer who is now the proud owner of their very own 1MW fusion reactor looks almost certainly military in origin, and could well be SPAWAR. Space And Naval Warfare Systems Command. Should we now call it the NavyCat?"

The Rossi E-cat is almost certainly a scam. That will be revealed in the next few years. If by some miracle, it is not a scam, or he has actually found another mechanism even...

You people are completely crazy. You've dozen of scientific publications about process, which has been studied for twenty years and you're speculating again and again about Rossi's E-cat, which is completely undocumented.

Umm...We're talking about the E-cat because someone else brought it up....and how you entered the conversation without considering what you were saying the context of the other comments, I think we both assumed you were shilling for it.

So we were expressing our skepticism of it. I'm not sure what you're trying to say. We didn't bring it up.

I checked Rossi's report which is on MSNBC. It is on this web site here: http://www.msnbc....uuIhlaUk . Remember to not add spaces where the line breaks are....dont be a n00b! The report, for those who are afraid of MSNBC, is a 400 watt input nets a 10,000 watt output for several hours, when more fuel is needed. I will take that camping in my converted bus and live in the hinterland for years and never have to buy diesel for my generator but maybe just to start it once, as the inverter will always have enuf stored to restart the Rossi Fusion generator. The Fusion generator will recharge the batteries through the inverter and the RV will run ...f-o-r-e-v-e-r!!!

This is so embarrasing, these comments make me cringe...the biggest bunch of idiots I've ever heard, talking like experts, making fools of yourselves with every word and sentence..at least some of the drivel is in formed sentences.There's only one thing missing in this whole discussion...A CLUE!

Umm...We're talking about the E-cat because someone else brought it up....

But Piantelli and Foccardi brought the cold fusion at pure nickel before twenty years. Why we aren't talking about it? Is it because Mr. Rossi is easier target for various skeptics? But he is private person, so he is not obliged to reveal anything from his research, until he and his clients are comfortable with it.

Many of you are saying, the cold fusion research requires the rigorous scientific approach. I can fully agree with it - so if you want to support the basic science and scientific method, you should be interested about modest scientists, who found the cold fusion and published all this stuff in normal scientific way.

The interest of publicity about Rossi is unhealthy with respect to respect to science as such. The Rossi didn't invented his stuff, he even never wrote a single article about it. The people in this thread are just demonstrating, they don't care about scientific method at all.

A clue? IMO whole thing is crystal clear. The mainstream physics takes money of tax payers for development of technologies like the ITER, while ignoring the technology, which is way safer and cheaper for twenty years. Now their proponents are focussing to A.Rossi instead to original founders of this technology to cover this twenty years ignorance and the waste of research money.

The people, who are able to manage the complex physical theories are indeed able to realize these simple connections. Many people like to talk about Rossi like about cheater without single evidence - but what the physicists working at alternative technology actually are? They're fraudsters - it just depends on the observational perspective, in which we would judge the whole case.

Despite the complexity of ethical issues involved here, the overall result is desolating. We are burning irrecoverable supplies of fossil fuels, polluting life environment with carbon dioxide, smog and nuclear waste, spending money in useless research and maintaining wars for oil whole years - while ignoring the findings of cheap and safe technologies, which would make all this completely unnecessary. The human civilization in its current stage became apparent enemy of its own progress.

We people as whole should learn from this faux-pass and to adopt the public control rules, which would prohibit its repetition for future. To make make mistakes is normal, but to repeat the same mistake again and again is just stupid and reprehensible.

ITER project is a complete waste of money of tax payers. It will never produce any energy.

E-Cat could replace fossil fuels "soon"

The people don't care if cold fusion is working or not. After all, they ignored it twenty years. The do prefer nuclear war instead.

Your statement doesn't make any sense .. How does not believing in cold fusion mean you believe in nuclear war ?

Anyway i guess you equate nuclear war with nuclear fission, which has a proven track record as a stable energy source for decades. Only problem with fission is it has been vilified by the coal mafia by generous funding to anarchists like Greenpeace and the anti-nuclear lobby.

This is so embarrasing, these comments make me cringe...the biggest bunch of idiots I've ever heard, talking like experts, making fools of yourselves with every word and sentence..at least some of the drivel is in formed sentences.There's only one thing missing in this whole discussion...A CLUE!

How does not believing in cold fusion mean you believe in nuclear war ?

When the oil price will exceed 300 - 400 USD/gallon, then the geopolitical tension connected with it will initiate nuclear war automatically. The cold fusion is currently the only way, how to limit the consumption and price of oil significantly, the nuclear or renewable energy sources cannot compete with it.

How does not believing in cold fusion mean you believe in nuclear war ?

When the oil price will exceed 300 - 400 USD/gallon, then the geopolitical tension connected with it will initiate nuclear war automatically. The cold fusion is currently the only way, how to limit the consumption and price of oil significantly, the nuclear or renewable energy sources cannot compete with it.

A couple of dubious assertions here.

First, it's unlikely we'll ever see oil go that high, assuming you are referring to 2011-adjusted dollars. Why? A combination of market forces, reliance on new energy sources to replace oil, discovery of new oil sources and methods of acquisition, and the very fact of high-priced oil will quicken the switch away from it, thus stabilizing prices.

Second, proposing that any action will "initiate nuclear war automatically" is a stretch. In other words, you're just using fear tactics.

Smegma entanglement accounts for half of the undisclosed catalysts currently being disclosed. The method used is not important. The assumption that Rossi is a "Balding Italian" should be laid to rest. As stated earlier "Radiation Radically Alters Our Perception of the Space/Womb Continuum."

Smegma entanglement accounts for half of the undisclosed catalysts currently being disclosed. The method used is not important. The assumption that Rossi is a "Balding Italian" should be laid to rest. As stated earlier "Radiation Radically Alters Our Perception of the Space/Womb Continuum."

Iran has no Nuclear weapons. that is such bull-crap.Let the Zionists give some proof first instead of lying their arses off.

Yes, indeed. Let's wait until the country calling for our complete extermination has the ability to do so BEFORE we act upon it.

I do not condone war or violence of ANY KIND, not even to defend one's self from an attacker. This is seated at the core of my intellectual and rational being, unfortunately on top of that is many layers of instinct and irrational motivation to live. It's a battle we must ALL realize and come to understand for it may never be resolved and yet it affects us at this very moment.

For a pellet that weighs a few grams at 11 degrees...I would imagine that it is easily affordable.

And at those prices, obviously it can't be more than a few hundred watt hours per pellet. Industrial efficiencies can be much higher than your freezer. it probably takes more energy and care just to handle the frozen pellets.

Now let's compare that to the amount of energy it took to build a 20 billion dollar power plant with giant ass lasers that use exowatts of power...

Er so whats the cost per pound of deuterium and tritium frozen solid to 11 degrees above absolute zero Kelvin? And how do you compare its use cost-wise in a multi-billion $ laser fusion plant vs a multi-billion $ superconducting tokamak fusion plant? Be specific please.